The sudden stirring of the foot during sleep is called sleep jumping. This condition tends to occur when one has just fallen asleep and is also known as sleep twitching, or pre-sleep myoclonus. The cause of this condition is not well understood, and it is speculated that it may be caused by the instability of the superior reticular activation system during the transition from wakefulness to sleep. Sleep terrors are likely to occur with excessive intake of caffeine, or other excitatory substances, strong physical labor or exercise, drinking alcohol or using sleeping pills before sleep, which can make the occurrence of sleep terrors less frequent. Most of the episodes are single and have little effect on the person. If the episodes are frequent and lead to awakenings, they may make the patient anxious about falling asleep and lead to difficulty in falling asleep, in which case sleeping pills are needed for treatment.